(Sheesh, I should have posted about this months ago.)

ACK is a DOS-era toolkit for making simple Ultima-style RPGs, based on Stuart Smith's seminal Adventure Construction Set. Development stopped for a long time, but the author has recently begun to release new versions, bundled with a copy of DOSBox.

The newest pack-in game, Ultima IV Part 2: Dude, Where's My Avatar?, looks pretty bizarre, but I don't want to play it until I get more familiar with the original Ultima games (don't look at me like that). There is also a tutorial module explaining most of the features.

I had an adventure game planned, but it might be a while before I get back to working on it. I recall a monsters-destroying-city game being in the works, and the author of the program had a decent (albeit years old) historical adventure about a caravan of settlers.